Phase Analysis of Charge Density Waves in Kagome Superconductors

Charge density waves (CDWs) can be analyzed using Scanning Tunneling Microscope (STM) images. In this study, we demonstrate an approach to investigate CDWs by registering STM images of the same sample at different bias voltages, followed by an Inverse Fourier Transform and line cuts of the resulting images. This process allows us to create a waterfall plot, revealing the phase shift in the charge density wave. The phase shift provides crucial insights into the positioning of the Charge Density Wave gap relative to the Fermi Level. Our investigation focused on a sample of crystal CsV3Sb5, and we discovered that the pi phase shift occurs at an unexpected sample bias of 280 mV instead of the expected 0 mV.